PIP reinstated prior to tribunal but short!!

Ally13

Hi everyone. I'm new. The DWP contacted me shortly after their tribunal deadline. This resulted in them overturning their decision to remove my PIP entitlement. I have received a lump sum of £1980.25 sand my first month payment of £290.60. However, although it's difficult to work out due to the increase on 6th April, they have paid me at least £272.40 less than they owe me. I have assumed that 100% of PIP 4 weekly payment is paid in arrears so I can't have over-estimated. I have received no breakdown from the DWP telling me how they calculated this amount. Can I expect this to come at some point or do I have to call them? Thanks.

As a result of their decision last January, I had to move out of my home of 10 yrs and am now homeless (I don't sleep out, I have various friends who 'share me out' but this is a bad place to be in at 62 yrs old with a serious mental health disability.